The present invention relates to a satellite navigation receiver system, and, in particular, to a multi-antenna-GNSS receiver system to raise the probability of line of sight (GNSS=Global Navigation Satellite System).
In difficult Global Navigation Satellite System scenarios, where satellite signals are shadowed by obstacles around the receiver, the receiver is not able to continuously track all signals of available satellites.
The known technology provides some attempts to solve this problem.
In “Concept of Synthetic Aperture GNSS Signal Processing Under Canopy” (see [1]), it is proposed for difficult scenarios to raise the received satellite signal power by a synthetic aperture radar.
In multi-antenna phased-array receivers, GNSS signals from different spatial locations are combined coherently forming an optimized synthetic antenna-gain pattern. Thereby, multipath signals can be rejected and the line of sight received signal power is maximized.
Both solutions have commonly the same problem that the distance of the antenna phase centre must be quite short, so no new sky view around obstacles is expected.
In CN2478119 (Y) (see [2]), a GPS multi-antenna switch (GPS=Global Positioning System) is described to reduce receiver hardware cost by using a single receiver with multiple antennas for dam deformation monitoring. With this technology only small movements can be detected. The provided multi-antenna switch is therefore not suitable for dynamic applications.
In Sauter (see [3]), it is described that in a deep forest environment, no position solution with an accuracy of below one meter can be gained with GNSS.